Internal-combustion engine



Feb, B2 mm W. R. GRISWOLD INTERNAL COMBUS TION ENGINE Filed Aug 1926 2Sheetsfieet l Feb, 12, 1929. 1,701,563

W. R. GRISWQLD INTERNAL COMBUSTION ENGINE F2125 Aug. 2. 192 6 2Sheets-Sheet 2, 40 7 3U 29 "*T, $21; .iL 48 ,9 d? 47 29 I I w E 5 43 Z 2H I 2Z8 18 Patented Feb, 12, iaze.

siren stares ,PATEN @EMQE,

WALTER It. GRISWQLLLGF DETROIT, MICHIGAN, A$SIGNOR T PACKARD MOTOR CAR0F DETROIT, MICHIGAN, A GORPORATIQN Uh MICHIGAN. C

INTEEN'ALrCOMBUSTKON ENGINE.

Application filed August 2, 1926. Serial No. 128,423.

This invention relates to internal combustion engines, more particularlytothe valve operating mechanism of such engines, and it has for one ofits objects to provide a valve gearing for such an'engine which shall besubstantially silent in operation.

Another object of the invention is to provide such an engine valveoperating mechanism in which the clearance between the valve and itsoperating member shall be a minimum and in which adjustments of theclearance be readily made.

Another object. of the invention. is to provide driving mechanism forthe valve operating mechanism of an internal combustion engine whichshall be quiet and efficient, and which shall not require provision forthe relief of shock as the valve starts to open.

Another object of the invention is to provide an engine having adequatelubrication of all parts of the valve operating mechanisin which aresubjected to wear, and in which the mechanism of any particular valvemay be disassembled or adjusted without disturbing the adjustment orsetting of any of the other valves.

Uther objects of the invention ,will appear from the followingdescription'taken in connection with the drawing, which forms a part ofthis specification, and in which:

Fig. 1 is a view, partially broken away and partially in transversevertical section,-

of an internal combustion engine constructed in accordance with theinvention;

Fig. 2 IS an enlarged detail view, partially in elevation, and partiallyin section substantially on the lines 22 and 2 of Fig. 1;

Fig. 3 is an enlarged detail view, partially I in elevation andpartially indvertical section thru one of the valve operating rockerarms and itssupport;

Fig. 4 is a View, partially in plan and partially in horizontal sectionthru the rocker arm shown in Fig. 3;

liigsfS and 6 are enlarged detail sections substantially on the finest-5 and 66 of Fig. l;

Fig, 7 is a detail section substantially on the line 77 of Fig. 3, and

Fig. Sis a fragmentary vertical section thru a pair of rocker armsshowing'a modified form of the clearance adjusting mechanism.

' The present invention, while it may be ap-;

plied to the valve operating mechanism of all types of engines havingreciprocating valves, is particularly adaptable to engines in whichvalves of the poppet type are mounted in the cylinder head with thevalve stems disposed upwardly, and in which the valves are actuated byrocker arms mounted in the head and connected by push rods to a timingshaft located at the side of the engine. Such valve-in-the-head enginesare recognized as a type having numerous advantages of accessibility andsimplicity, but these ongines have heretofore presented certaindifficulties in operation, one of which is exces, sive noise of thevalve operating mechanism. This is caused in part by the unavoidableclearances in the train of actuating mechanism, but the necessity ofallowing a considerable clearance between the valve stem and itsactuating member, to compensate for temperature changes in themechanism, is more largely responsible for such noise.

@ther difliculties presented by this type of valve mechanism are thenecessity of frequent adjustment of the actuating rockers, theinconvenience and difliculty. of making such adjustments easily andaccurately, and

inadequate lubrication of the moving parts ated from 'acam shaftarranged to drive the lower ends of the push rods through suitable camfollowers. lhe cams in such shafts are usually designed with longeasement curves in order to diminish the shock and noise caused by a tooabrupt engagement of the lift portion of the cam with itsfollower, andthis frequently requires a compromise modification of that valveoperationwhich would be dictated by purely theoretical considerations.in the present invention is provided an engine having valve mechanism ofthe overhead type in which the shortcomings of previous valve mechanismsof the type referred to, are obviated.

Referring to the drawing, at is shown an internal combustion engine,preferably of the well known valve-in-the-head type,

having a crank case 11 provided with a de- I tachable oil pan or sump12, and surmounted crank case 11 is journaled the usual engine crankshaft 15, the cranks of which are connected to pistons 16 slidablymounted in the cylinders 13, by connecting rods '17 of any suitableconstruction.

I The engine cylinders 13 and head 14 are provided with suitablepassages 18 for cooling fluid, and the head is provided with acombustion chamber 19 for each of the cylinders 13, each of thesecombustion chambers communicating with exhaust and intake passages, oneof which is shown at 20. The passage 2O communicates through a port 21with the combustion chamber 19, and this port 21 is controlled by asuitable valve22, preferably of the well known poppet type, having astem 23 which is slidably mounted in a guide 24 in the engine head 14.The valve 22 is also provided with a suitable spring 26, connected inany well known manner to the valve stem 23 and adapted to urge the valvetoward closed position.

Mounted on the engine head 14 is a row of pedestals or other suitablesupports 27 which are secured to lugs 28, integral with the head 14, inany convenient manner as by bolts or studs 29. These pedestals 27 areprovided at their upper ends with eyes 31, in which are secured tubularpivotal supports, such as the arbors 33, disposed longitudinally of thehead 14. The arbors 33 are provided with suitable holes 34 for thepassage of the bolts 29,;which may be of reduced section to provideclearance for easy removal of the arbor. Mounted on the arbors 33 arerocker levers or arms 36, preferably of channel section as shown in Fig.7, having downwardly disposed flanges 37 connected by a web 38, whichhas a plane upper face 40. This web is cut away at the fulcrum end ofthe lever, and the flanges are provided with suitable eyes 39 by meansof which they are pivotally mounted on the arbor. Pivotally mounted onthe arbor 33 between the flanges 37 of the rocker lever 36 is acompanion rocker lever 41having-a tappet portion 42 on its'lower faceadapted to contact and operate the upper end of the valve stem 23 andhaving at its fulcrum end an eye 43, disposed between the eyes 39,surrounding the arbor 33.

The levers 36 and 41 are adapted to be adjustablyconnected at theirouter ends in any suitable manner as by means of a bolt 44, fixed in.theweb 38 and projecting downwardly thru the lever 41. (lo-operating withthe bolt 44 is a tubular nut 46, through which the bolt 44 passesfreely, and which is threaded externally in the arm 41, and a nut 47 isthreaded on the lower end of the bolt 44 so that it may be screwed intoengagement with the end of the tubular nut 46. vA bushing 48 {may beplaced on' the arbor 33 to support the eyes 39 and 43 if desired Theselevers 36 and 41 are thus rigidly connected and oscillate together as asingle arm about the arbor 33, and angular relation between them aboutpositcsideofthevalve stems23 is a row ofpcdcstais or supports 49,similar to the pedestals 27, each of which is mounted on a lug 51 andconnected thereto by bolts 52. and which have at their upper and eyes 53in which a. tubular arbor 54 is mounted. This arbor may be continuous.having holes 55 for the passage of the bolts 52, or it may be made inabutting sections. the ends of which have semi-cylindrical recesses toentertain the bolts. The arbor 54 is adapted to support spaced rockerarms 56 provided at their ends with eyes 57 and bushings 58 by means ofwhich they are pivotally mounted on the arbor 54. The lower face of thearms 56 has a surface 59 curved longitudinally of the rocker lever whichcurve is conjugate to the upper face 40 of the rocker lever 36. Thesecurves may be of any desired form to give the desired valve travel butthey are preferably of a nature adapted to roll one upon the other witha minimum of sliding movement. The portion of the curved surface 59toward the fulcrum end of the lever 56 is preferably tangent to thecircular portion 60 of this lever which forms the eye 57 by which it ismounted on tion that as the forked end of the lever 56 is moveddownwardly its curved surface 59 will roll upon the plane surface 40 ofthe lever 36 and depress the latter thus also depressing the lever 41and opening the valve 22 against its spring 26. The point of contactbetween the surfaces 59 and 40 moves along the curves of these surfacesduring opening and closing of the valve, and these su-rfaces'arepreferably so related that during the dwell portion of the valve cycle,when the valve is closed, the circular portion 60 of the curve of thearm 56 is in contact with the surface 40, .so that motion of the arm 56during this period does not produce any corresponding motion of the arm36 or of the valve 22.

The upper rocker lever 56 is adapted to be oscillated by suitable rods63, which are preferably tubular in construction as shown in Fig. 1, andeach of which is connected at its upper end by a turn-buckle 64 to aneye 66 adapted to cooperate with the pin 62 of the clevis 61 previouslydescribed. The lower end of the rod 63 is preferably threaded into anextension 67 integral with one portion of a two part bearing member 68,disposed within the crank case '11. These connecting'bearings 68 aremounted on and adapted for actu-.

' ation by the cranks 69 of a crank shaft 71,

which is mounted in the crank case'll parallel to the engine crank shaft15. The crank shaft 71 is preferably journaled in suitable bearings 7 2supported by brackets 73, which may be made in two parts and connectedby the bolts 74 if desired. 'llhese brackets are mounted in alongitudinal opening 7 5 in the crank case 11, and form a cover plate 76therefor, which cover plate is removably secured to the crank case 11 inany convenient manner as by bolts 77, so that'the entire timing shaftassembly comprising the brackets 73, bearings 72, shaft 71 and crankbearings 68 may be re moved as a unit from the crank case 11.

The crank shaft 71 is adapted to be driven at one end thereof from theengine crank shaft 15 in any convenient manner, but in timed relationthereto, as by means of gears or a chain and sprocket (not shown); thisdrive being in all respects similar to the drive in common use for thecam shafts usually em ployed as timing shafts in internal combustionengines. It will be apparent that as the crank shaft 71 is rotated, itsmotion will be transferred through the cranks 69, bearings 68,extensions 67 and rods 63, to the/outer end of the upper rocker levers56, which will be oscillated in the manner previously described tooperate the engine valves.

\ The rods 63 are adapted to pass through a suitable opening formedbetween the block of, cylinders 13 and a cover plate '81, which coverplate is removably secured over an opening 82 in the casting of block 13in any well known manner. it will be seen that with the cover plate 81removed, the lower ends of the rods 63 may be readily disconnected fromthe members 67 after the upper ends of the rods have been disconnectedfrom therocker levers56 by removal of the clevis pins 62. After removalof the rods 63 thru the opening 82, the timing shaft assembly may beremoved as previously described by taking oh the cover plate 7 6. inthis way access to the drive for the valve gearing, for purposesofadjustment, inspection or repair is readily efiected.

Adequate lubrication is provided for the rocker arms36 and 56 byconnecting the tubular arbors 33 and 541- to any suitable source oflubricant under pressure, as for example the engine oiling system (notshown). The rocker levers 36 and 41 are each provided at their hubportions with a radial oil passage 83, by means of which lubricant isconducted from the hollow arbor 33 to the bearing hubs of these rockerlevers, thus providing adequate lubrication at this point. The upperrocker lever 56 is provided with a longitudinal passage 8 1 connectingthrough a radial duct with the interior of the tubular arbor 53, by

means of which oil is conducted from this turocker arm 36.

bular arbor to lubricate the clevis pin 62 and the bearings of theclevis 61 and the rod con-. nection 66 therewith. This passage 84 may beprovided with 'a branch passage 86 by means of which lubricant is alsoconducted between the contacting surfaces 59 and 40 of the"1'ocker leverassembly.

The timing shaft, assembly is also lubricated from the engine systemthrough a conduit 89 formed in the crank case 11 and extendinglongitudinally of the engine. Suitable ducts 91 communicate with theconduit 89, and also register with ducts 92 formed in the brackets73,-Which conduct lubricant to the timing shaft bearings 72. Each ofthese hearings has a metering slot 93, adapted to communicate once ineach revolution of the rocker arm 36 has a downwardly disposed portion101 in which is threaded a setscrew 102 having a conical point103-adapted to enter between the web 38 and the lever 41 to regulate theangular relation of these members about the axis of the arbor 33. Thesemembers are urged together by a bolt 104, the head of which is securedfrom turning with respect to the web 38 and which has a nut 105contacting the lower surface of the lever arm 11. It will be evidentthatby slacking 0d the nut 105, the parts 38 and ll may be sepa. ratedto any desired degree by screwing in the set screw 102 to take up theclearance between the rocker assembly and the valve stem, after whichthe parts may be'clamped in adjusted position by tightening up the nut105.

lhis adjustment may be readily performed It will be evident that in themechanism of y the present invention is provided valve ace tuatinggearing in which the clearance be tween the valve stem and its actuatingmember may be maintained a minimum, as low as .0015 inch, since anyvariations in the length ofthe .valve stem or of the push rods 63,tending to decrease this clearance, will simply result in a shifting ofthe point of contact between the lower surface '59 of the rockerarm 56and the upper surface 40 of the It will also be evident that thisinvention provides a mechanism in which the wear of the parts is aminimum, since the rocker levers roll together on their conjugate faceswith a minimum of friction. Furthermore, these surfaces, as well as allwearing parts of the mechanism are adequately lubricated under pressurefrom the engine oiling system.

In the event that it becomes necessary to make a replacement of a valveor its spring, or an adjustment of any particular valve, it is onlynecessary to disconnect the push rods of the valves in that cylinder towhich the adjustment appertains, by removing the clevis pin 62, dismountthe arbor 5-1 by removal of the stud bolts52, and turn back the rockerlevers 36 on their pivotal mountings at 58. In this way the valvesrequiring attention are readily exposed without the necessity ofdismantling: the entire valve mechanism.

It will also be observed that no provision is necessary to lessen theshock of engagement of the parts as any given valve starts to open,since, the movement of the timing shaft 71 is uniform; there being nosudden engagement as in the case of acam operated device. In this waythe practical cycle of operation of a valve can be made to much morenearly agree with the theoretical cycle thereof.

It will be understood that various forms of the invention other thanthose described ibove may be used without departing from ihe spirit orscope of the invention.

I claim: v

1. The combination in an internal combustion engine having a poppetvalve of valve operating mechanism comprising a two part rocker armhaving a common fulcrum for the parts, a second rocker arm adapted tocontact one part of the first named arm and having a conjugate contactsurface, means on the other part of the two part arm to operate thevalve, means to adjust the anglebetween the parts of said arm, and meansto operate the second named arm in timed relation to the engine. 4

2. The combination in an internal combustion engine having a poppetvalve of valve operating mechanism comprising contacting rocker armsfulcrumed at opposite sides of said valve, one of said arms having twoparts,

valve contacting means on one of said part-s, screw means to adjust theangle between the parts, and means to operate the other arm in timedrelation to the engine.

3. In combination in an internal combustion engine having a poppet'valve, a valve mechanism comprising parallel pins on opposite sides ofthe valve, a forked lever fulcrumed on one said'pin, a lever fulcrumedon said pin between the, branches of the forked lever and having a planeupper surface, a leverfulcrumed on the other pin having a lowor surfaceconjugate to and adapted to roll on the said plane surface, meansadjustably connecting the ends of the two first named levers and meansto operate the last named lever in timed relation to the engine.

4. In combination in an internal combustion engine having a poppetvalve, a valve mechanism comprising parallel pins on opposite sides ofthe valve, a forked lever fulcrumedon one of the said pins and adaptedto operate the valve, a lever fulcrumed on said pin between the branchesof the forked lever and having a plane upper surface, a lever fulcrumedon the other pin having a surface adapted to roll on the said planesurface to provide the lift and dwell of the valve, and means to adjustthe plane surface lever about its fulcrum relative to the forked leverto vary the clearance between said levers and the valves.

5. A valve actuating mechanism for an internal combustion engine havinga lubricating system, comprising a pair of superim posed levers havingconjugate contact surfaces and fulcrumed at opposite ends, and meansconnected to the engine lubricating system to meter lubricant to thefulcrums of levers and tosaid surfaces.

6. A valve actuating mechanism for internal combustion enginescomprising a lever to operate the valve and having a plane surface, alever having a conjugate surface adapted to roll on said plane surfaceand having a cylindrical surface tangent to the conjugate surface, andmeans to oscillate the second lever in such timed relation to the enginethat the conjugate and the cylindrical surfaces cooperate with the planesurface during the lift and the dwell of the valve respectively.

I 7. A valve actuating mechanism for internal combustion enginescomprising a valve operating lever having a plane surface, and a secondlever to'actuate the first lever having a surface mcludmg two curvedportions, one of said portions cooperating with the plane surface duringvalve lift, and the other portion cooperating with the plane surfaceduring valve dwell.

8. A valveactuating mechanism for internal combustion engines comprisinga valve operating lever, and a lever having contiguous curved surfacesadapted to make rolllng contact with the operating lever, one ofsaidcurved surfaces oscillating the operating lever during valvelift, andthe other curved surface contacting the operating lever during valvedwell.

9. A valve actuating mechanism for internal combustion enginescomprising two le-V vers one of which is'adapted to operate the valve, acommon fulcrum for said levers,

means adjustably connecting said levers, a-

third lever having a separate fulcrum and adapted to operate the otherof the first mentioned levers, and means actuating said third lever intimed relation to the engine.

In testimony whereof I affix my signature. WALTER R. GRISWOLD.

